Recent advances in semiconductor design and fabrication methods enable ever increasing miniaturization of electronic circuits. Complete systems comprising microprocessors, communication logic and, in particular, memories can now be found on a single semiconductor chip. Such systems-on-a-chip (SOC) have a multiplicity of technologies that previously had a high space requirement as separate components on a circuit board.
While, in the past, semiconductor chips were dominated by logic functions and separate memories were provided externally, modern integrated circuits increasingly require embedded memories on a semiconductor chip itself. Embedded memories may be present in semiconductor chips as different memory blocks in different sizes and forms. As a result of the integration of memories on a semiconductor chip, it is possible to save space. In addition, as a result of eliminating or reducing interfaces and speed-impeding factors such as circuit boards, the speed of memory accesses can be increased.
Embedded memories in a system-on-a-chip have to be very reliable and tested accordingly. Therefore, a memory self-test device, sometimes referred to as a “memory built-in self-test” (MBIST) device, is usually provided in a system-on-a-chip having embedded memories, said device being tailored to the embedded memories provided in the system. Such a device then carries out a memory self-test, for example during or after the fabrication of the corresponding semiconductor chip.